1. Field of the Invention
The present invention relates to the binding of a boot on a gliding board. In particular, the invention relates to an interface device between the structure used in binding the boot to the gliding board, as well as a gliding board in combination with such an interface device. More particularly, the invention relates to the practice of alpine skiing, in which the skier descends very steep slopes at high speed, with each foot affixed to a separate gliding board. In alpine skiing, the boots and the devices for binding the boots to the gliding boards are configured so that the front and rear of the boot are attached to the gliding board and substantially immobilized vertically in relation thereto.
2. Background Information
Gliding on snow, such as skiing, is a relatively old sport, and a number of products have been developed to make the practice ever more enjoyable, more efficient, and more accessible. New gliding techniques have appeared more recently and somewhat changed the rules of practice, but few have fundamentally challenged the principle of binding the boots of the user on the gliding board. In order to improve the safety of the users, so-called “safety bindings” have been developed, which provide for the release of the boot from the gliding board in the event of a fall. However, the known devices for affixing a boot to a gliding board are not optimal and their use is a source of discomfort for the users.
One of the sources of discomfort, and especially for alpine skiers, occurs at every turn. While moving in a straight line down the slope, the skier undergoes a deceleration when he/she initiates a turn. But the inertia of the body tends to unbalance the skier forward. Conversely, upon exiting a turn, the acceleration of the skis tends to unbalance the skier rearward. The skier must constantly counteract against these unbalance-causing forces.
The structure of a binding generally comprises at least one front retaining device referred to as the “toe piece”. This is the case for all skiing practices, whether alpine skiing, cross-country skiing, ski touring, and even telemark skiing. In the case of alpine skiing, the structure of a binding also comprises a rear retaining device referred to as the “heel piece”. The boot is inserted between the toe piece and the heel piece, these elements being capable of being fixed on a base, which may or may not be a common base, also referred to as an interface. Thus, the combined action of these two retaining devices makes it possible to longitudinally affix the boot to the gliding board. To block the movement of the boot along a direction, perpendicular to the sole of the gliding board and generally vertical during use of the gliding board, the toe piece and heel piece are each equipped with a stop mechanism acting on the boot.
The base to which the toe piece and heel piece are fixed is generally stationary in relation to the gliding board, so that the boot is fixedly held on the gliding board. In the case in which the toe piece and heel piece are fixed to a common base, i.e., the same base, a limited relative movement may be provided between the base and the ski to ensure that the base does not interfere with the bending of the ski. In general, one of the ends of the base, or the center thereof, is solidly fixed to the ski without possible relative movement with respect to the portion of the ski to which it is fixed, whereas the opposite ends are capable of sliding in relation to the ski when the ski bends. This arrangement is such that the base does not interfere with the bending of the ski, and it provides a ski for which the skier's foot is always stationary in relation thereto. Therefore, the terrain irregularities, if substantial, tend to unbalance the skier, as the effects of such irregularities are transmitted from the ski to the skier through the bindings.
The document WO-A-00/10659 and its family member U.S. Pat. No. 6,131,939 disclose a ski, the upper surface of which, opposite the gliding sole, is equipped with a base extending over the major portion of the length of the ski, and a central zone of which is provided to receive a device for binding a boot. The ski is provided with a longitudinal rail forming a slide with a complementary groove provided in the base. The base, in the area of its central zone, is fixed to the ski by screws. Thus, the ends of the base are movable in translation in relation to the ski, along the longitudinal direction of the ski. The ski and the base are curved in a direction perpendicular to the gliding sole of the ski, the concave side being turned downward. The front and rear ends of the ski comprise stops for limiting the movement of the ends of the base in relation to the ski, which are maneuverable between an unlocked position, in which the translational movement of the ends of the base in relation to the ski is authorized, and a locked position, in which the ends of the base are fixedly affixed to the ski. In the locked position, the base increases the stiffness of the ski in longitudinal bending. In the unlocked position, the sliding of the ends of the base in relation to the ski results in the base not opposing the longitudinal bending of the ski. However, whether in the locked or unlocked position, the skier's foot remains stationary in relation to the ski.
For a given ski, and once the safety bindings are mounted, the position of the foot of the skier in relation to the ski is fixed information. In general, ski manufacturers recommend a predetermined position for each ski model. This position is marked on the ski by a line referred to as the “boot center mounting point” because the ski boot also has a “boot center” reference mark in its middle. When mounting the ski bindings, or when the bindings are being adjusted by a specialized technician at the ski rental store, it is strictly required to have the “boot center” reference mark of the boot correspond to that of the ski.
On occasion, for a particular practice, a user can choose not to follow the recommendation of the manufacturer, but rather to mount his/her bindings so that the “boot center” reference mark of the boot either forward or rearward in relation to the reference mark of the ski. However, no device exists for displacing the ski bindings during practice, i.e., while skiing, e.g., such that the “boot center” point of the boot moves longitudinally in relation to the “boot center” point of the ski.
Furthermore, there are damping means positioned between the base and the skis, which are supposed to reduce the effects of irregularities in the terrain. For example, rubber plates are sometimes positioned to play this role. Unfortunately, the effect of these damping means is limited, as they act along a vertical direction.
Therefore, there exists a need to improve the practice of skiing by providing users with new equipment that improves performance and efficiency, while also improving comfort during use.